Vacuum insulated articles and methods of making same

ABSTRACT

The present disclosure provides vacuum insulated articles having two—or more—insulated volumes at reduced pressure. An article may include a first vent communicating with a first insulating space, a second vent communicating with a second insulating space, a first circular insulation seal sealing the first insulating space at the first vent; and a second circular insulation seal sealing the second insulating space at the second vent. Also provided are methods of fabricating vacuum insulated articles.

RELATED APPLICATION

The present application is a continuation of now-allowed U.S. patentapplication Ser. No. 14/627,271, “Vacuum Insulated Articles and Methodsof Making Same,” filed Feb. 20, 2015, which application claims priorityto U.S. Provisional Patent Application 61/942,323, “Vacuum InsulatedArticles and Methods of Making Same,” filed Feb. 20, 2014 Both of theseapplications are incorporated herein by reference in their entiretiesfor any and all purposes.

TECHNICAL FIELD

The present disclosure relates to the field of vacuum-sealed articles.

BACKGROUND

Although useful, vacuum insulated structures may have some limitationswhen used in applications where mechanical impacts can lead to breakageof vacuum seals or the jacket walls, and thereby the vacuum insulationis lost. Moreover, to increase the insulation capabilities of the vacuuminsulated structure, usually the vacuum chamber has to be increased insize, and many applications do not allow for such increase of thestructure's volume. Accordingly, in light of these deficiencies of thebackground art, new and improved vacuum insulated containers aredesired. Methods for fabricating such improved structures are alsoneeded.

SUMMARY

In one aspect, the present disclosure provides vacuum insulatedarticles. An vacuum insulated article may include an outer wall, aninner wall, and a middle wall (the middle wall being disposed betweenthe inner and outer walls), each of the outer wall, the inner wall, andthe middle wall having a cylindrical shape that are concentric or nearlyconcentric to each other; a first insulating space formed between theouter wall and the middle wall; and a second insulating space formedbetween the middle wall and the inner wall. A vacuum insulated articlemay also include a first vent communicating with the first insulatingspace to provide an exit pathway for gas molecules from the firstinsulating space, the first vent being sealable for maintaining a firstvacuum within the first insulating space following evacuation of gasmolecules through the first vent, a second vent communicating with thesecond insulating space to provide an exit pathway for gas moleculesfrom the second insulating space, the second vent being sealable formaintaining a second vacuum within the second insulating space followingevacuation of gas molecules through the second vent, a first circularinsulation seal sealing the first insulating space at the first vent;and a second circular insulation seal sealing the second insulatingspace at the second vent.

In another aspect of the present disclosure, other vacuum insulatedarticles are provided. A vacuum insulated article preferably includes anouter wall, an inner wall, and a middle wall, each of the outer wall,the inner wall, and the middle wall having a cylindrical shape that areconcentric to each other, an area between the inner wall and the middlewall forming a first insulating space, and an area between the middlewall and the outer wall forming a second insulating space, a firstcircular ring arranged between the inner wall and the middle wall, thefirst circular ring having a first beveled edge circularly arrangedaround the first circular ring facing at least one of the inner wall andthe middle wall, a first vent formed at the first beveled edgecommunicating with the first insulating space, and a second circularring arranged between the middle wall and the outer wall, the secondcircular ring having a second beveled edge circularly arranged aroundthe second circular ring facing at least one of the inner wall and themiddle wall, a second vent formed at the second beveled edgecommunicating with the second insulating space. The vacuum insulatedarticle may further includes a first circular insulation seal sealingthe first insulating space at the first vent, and a second circularinsulation seal sealing the second insulating space at the second vent.

In another aspect, the present disclosure provides methods of formingvacuum insulated articles. These methods suitably include the steps offorming or providing a first tube having a first diameter defined by anouter wall, forming or providing a second tube having a second diameterdefined by a middle wall, the second diameter being smaller than thefirst diameter, forming or providing a third tube having a thirddiameter defined by an inner wall, the third diameter being smaller thanthe second diameter, positioning the third tube into the second tube toform a first annular insulating space between the third tube and thesecond tube, such that ends of the second tube and the third tube arepositioned so as to form a first circular vent between the end of thesecond tube and the end of the third tube. The methods also suitablyinclude drawing a vacuum on the first annular insulating space bycausing air to escape through the first circular vent, and sealing thefirst circular vent to preserve the vacuum within the first annularinsulating space. The methods may further include the steps ofpositioning the second tube into the first tube to form a second annularinsulating space between the second tube and the first tube, such thatends of the first tube and the second tube are positioned so as to forma second circular vent between the end of the first tube and the end ofthe second tube; drawing a vacuum on the second annular insulating spaceby causing air to escape through the second circular vent; and sealingthe second circular vent to preserve the vacuum within the secondannular insulating space.

The present disclosure also provides vacuum insulated articles, thearticles suitably comprising: an outer wall, an inner wall, and a middlewall, at least one of the outer wall, inner wall, or middle wall havinga planar region, an area between the inner wall and the middle walldefining a first sealed insulating space, and an area between the middlewall and the outer wall defining a second sealed insulating space; andat least one of the first sealed insulating space and second sealedinsulating space being at less than ambient pressure. By less thanambient pressure is meant that the pressure is suitably less than 760Torr. Pressures of about 10⁻¹, 10⁻², 10⁻³, 10⁻⁴, 10⁻⁵, 10⁻⁶, and evenabout 10⁻⁷ Torr are all considered suitable.

This disclosure also provides methods, the methods suitably includingarranging first and second surfaces at a distance from one another so asto define an overlap volume between the surfaces that has at least oneopening placing the overlap region into fluid communication with theenvironment exterior to the overlap volume, at least one of the firstand second surfaces having a first region having a curvature; effectinga vacuum on the overlap volume by causing air to escape the overlapvolume; sealing the overlap volume so as to preserve the vacuum withinthe overlap volume, the method being performed such that the curvatureof the first region is changed.

Additionally provided are methods of forming a vacuum insulated article,comprising forming a vacuum in a first space defined between an outerwall and a middle wall, at least one of the outer and middle wallshaving a planar region that overlaps the first space; forming a vacuumin a second space defined between the middle wall and an inner wall, atleast one of the middle and inner walls having a planar region thatoverlaps the second space; sealing the first space so as to maintain thevacuum in the first space; sealing the second space so as to maintainthe vacuum in the second space.

The disclosure also provides methods of forming a vacuum insulatedarticle, comprising with (a) a first tube having a first diameterdefined by an outer wall, (b) a second tube having a second diameterdefined by a middle wall, the second diameter being smaller than thefirst diameter, and (c) a third tube having a third diameter defined byan inner wall, the third diameter being smaller than the seconddiameter, positioning the third tube into the second tube to form afirst annular insulating space between the third tube and the secondtube, such that ends of the second tube and the third tube arepositioned adjacent to each other to form a first circular vent betweenthe end of the second tube and the end of the third tube; drawing avacuum on the first annular insulating space by causing air to escapethrough the first circular vent; sealing the first circular vent topreserve the vacuum within the first annular insulating space;positioning the second tube into the first tube to form a second annularinsulating space between the second tube and the first tube, such thatends of the first tube and the second tube are positioned adjacent toeach other to form a second circular vent between the end of the firsttube and the end of the second tube; drawing a vacuum on the secondannular insulating space by causing air to escape through the secondcircular vent; and sealing the second circular vent to preserve thevacuum within the second annular insulating space.

The disclosure also provides vacuum insulated articles, comprising anouter wall, an inner wall, and a middle wall, each of the outer wall,the inner wall, and the middle wall having a cylindrical shape, an areabetween the inner wall and the middle wall forming a first insulatingspace, and an area between the middle wall and the outer wall forming asecond insulating space; a first vent communicating with the firstinsulating space; a second vent communicating with the second insulatingspace; a first seal sealing the first insulating space at the firstvent; and a second seal sealing the second insulating space at thesecond vent.

The foregoing summary is neither intended nor should it be construed asbeing representative of the full extent and the scope of the invention,which additional aspects will become more readily apparent from thedetailed description, particularly when taken together with the appendeddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The summary, as well as the following detailed description, is furtherunderstood when read in conjunction with the appended drawings. For thepurpose of illustrating the invention, there are shown in the drawingsexemplary and preferred embodiments of the invention; however, thedisclosure is not limited to the specific methods, compositions, anddevices disclosed. In addition, the drawings are not necessarily drawnto scale. In the drawings:

FIG. 1A shows a cross-sectional perspective view of the vacuum insulatedstructure, and FIGS. 1B-1C showing close-up views of areas A1 and A2 ofFIG. 1A, respectively, according to an embodiment of the presentinvention;

FIG. 2 shows a cross-sectional view of a peripheral edge of a casing ofthe vacuum insulated structure, according to an embodiment of thepresent invention;

FIG. 3 shows a cross-sectional view of a peripheral edge of a casing ofthe vacuum insulated structure, according to another embodiment of thepresent invention;

FIG. 4 shows a cross-sectional view of a peripheral edge of a casing ofthe vacuum insulated structure, according to still another embodiment ofthe present invention;

FIGS. 5A-5D show different stages of a method of manufacturing a vacuuminsulated article;

FIG. 6 shows an alternative embodiment of the disclosed technology;

FIG. 7 shows an alternative embodiment of the disclosed technology;

FIG. 8 an alternative embodiment of the disclosed technology;

FIG. 9 shows an alternative embodiment of the disclosed technology;

FIG. 10 shows a container end cap according to the present disclosure;

FIG. 11 shows a container according to the present disclosure;

FIG. 12 shows an alternative embodiment of the disclosed technology; and

FIG. 13A depicts an alternative embodiment of the disclosed technologywith chambers that have exits that are characterized as having aconverging angle, and FIG. 13B depicts a further alternative embodimentof the disclosed technology.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The present invention may be understood more readily by reference to thefollowing detailed description taken in connection with the accompanyingfigures and examples, which form a part of this disclosure. It is to beunderstood that this invention is not limited to the specific devices,methods, applications, conditions or parameters described and/or shownherein, and that the terminology used herein is for the purpose ofdescribing particular embodiments by way of example only and is notintended to be limiting of the claimed invention. Also, as used in thespecification including the appended claims, the singular forms “a,”“an,” and “the” include the plural, and reference to a particularnumerical value includes at least that particular value, unless thecontext clearly dictates otherwise. Any documents mentioned herein areincorporated herein in their entireties for any and all purposes.

The term “plurality”, as used herein, means more than one. When a rangeof values is expressed, another embodiment includes from the oneparticular value and/or to the other particular value. Similarly, whenvalues are expressed as approximations, by use of the antecedent“about,” it will be understood that the particular value forms anotherembodiment. All ranges are inclusive and combinable. When referring to avalue, the term “about” means the value and all other values within 10%of the value. For example, “about 10” means from 9 to 11 and allintermediate values, including 10.

Vacuum insulated structures have many practical uses and can beconstructed as described, for example, in U.S. Pat. Nos. 7,681,299 and7,374,063 and in U.S. patent application Ser. No. 12/766,397 (allincorporated herein by reference in their entireties for any and allpurposes), in which tube walls and jacket walls are vacuum brazedtogether so that a vacuum chamber is formed between the tube and jacketwalls.

A first embodiment of the present invention is described with respect toFIG. 1A-1C, with FIG. 1A showing a cross-sectional perspective view of avacuum insulated structure 10 made of an inner cylindrical casing 20having a bottom portion 21 and being open at a side that is opposite tobottom portion 21, and an outer cylindrical casing 40 having a lidportion 41 and being open at a side that is opposite to lid portion 41,FIG. 1B showing a close-up cross-sectional view of the area A1 shown inFIG. 1A, including peripheral edge 45 of outer cylindrical casing 40 andperipheral edge 25 of inner casing 20, and FIG. 1C showing a close-upcross-sectional view of the area A2 shown in FIG. 1A. For descriptivepurposes, the description below makes references to an x, y, and zCartesian coordinate system that is depicted in FIGS. 1A to 1C, in whichthe x-direction is defined as one direction of a plane that is parallelto walls 22, 24, 26, 42, 44, 46, the y-direction is defined as anotherdirection perpendicular to the x-direction in the same plane, and thez-direction is a direction that is parallel to a central axis thatdefines the cylinder of casings 10, 20. In this respect, the negativez-direction is referred to as a bottom side or left side, and thepositive z-direction is defined as the top, upper or right side.

As shown in FIGS. 1A and 1C, an outer diameter of inner cylindricalcasing 20 and an inner diameter of the outer cylindrical casing 40 madesuch that the outer cylindrical casing 40 can be slid or screwed overthe inner casing 20, with gap G1 remaining between, as shown in detailin FIG. 1B. In the embodiment shown, inner cylindrical casing 20 can becomposed of a circular or oval shaped bottom portion 21, and cylindricalsidewalls 23, and outer cylindrical casing 40 can be made of circular oroval shaped lid portion 41 and cylindrical sidewalls 43 that are shorterin length than the sidewalls 23 of the inner cylindrical casing 20. Itis also possible that lid portion 41 and bottom portion 21 havedifferent shapes, other than oval or round, as long as they are matchingto allow casings 20 and 40 to be fitted into each other, forming gap G1therebetween. The cylindrical side walls 23 are formed of an inner wall32, an middle wall 30, and an outer wall 28, and bottom portion 21 isformed of inner wall 26, middle wall 24, and outer wall 22, and a vacuumspace V1 is formed between inner walls 32, 26 and middle walls 30, 24,and a vacuum space V2 is formed between middle walls 30, 24 and outerwalls 28, 22. Inner walls 32, 26, middle walls 30, 24, and outer walls28, 22, respectively, form structures can have a shape of an opencylinder with increasingly larger diameter, so that they are interposedin each other, as shown in FIG. 1A. Upper edge 25 of inner cylindricalcasing 20 is closed to form a vacuum seal. Upper edge 25 of innercylindrical casing 20 is close or abuts against inner wall 46 of outercylindrical casing 40.

Analogously to the inner cylindrical casing 20, outer cylindrical casing40 can be composed of cylindrical side walls 43 that are formed of aninner wall 52, an middle wall 50, and an outer wall 48, and lid portion41 is formed of inner wall 46, middle wall 44, and outer wall 42, and avacuum space V3 is formed between inner walls 52, 46 and middle walls50, 44, and a vacuum space V4 is formed between middle walls 50, 54 andouter walls 48, 42. Inner walls 52, 46, middle walls 50, 44, and outerwalls 48, 42, respectively, form structures that can have a shape of anopen cylinder with increasingly larger diameter, so that they areinterposed in each other, as shown in FIG. 1A The walls can be formed ofa single layer of sheet metal, e.g., stainless steel, copper, aluminum,and the like. It should be understood that walls between which a vacuumis formed may have the same thickness, but this is not a requirement.For example, a vacuum may be formed between a first wall havingthickness T1 and a second wall having thickness T2, where T1 is notequal to T2. Walls between which a vacuum is formed may have a thicknessratio (relative to one another) of about 100:1 to about 1:100, or fromabout 10:1 to about 1:10. It should also be understood that walls maybe—but need not be—cylindrical in conformation.

The upper edge 45 of inner cylindrical casing 40 may be closed to form avacuum seal, as shown in FIG. 1B. Gap G1 between inner and outercylindrical casings 40, 20 can be filled with an adhesive, e.g., exampleAccolite™, or can be soldered together to form an insulated inner area60 of vacuum insulated structure 10. A gap width (e.g., gap G1) may be,for example, in the range of from about 0.001 mm to about 10 mm, fromabout 0.01 mm to about 1 mm, or from about 0.1 mm or about 0.5 mm. Gapsof 0.1 mm are considered especially suitable.

The surfaces of inner and outer cylindrical casings 40, 20 that faceeach other may be matchingly threaded so that outer casing 20 can bescrewed onto inner casing 40. Also, as shown in FIG. 1C, cylindricalouter wall 48 is connected to an oval or circularly shaped outer wall 42so that outer wall 48 fits into a recessed edge 47 around the entirecircumference of outer wall 42, and are connected to each other bysoldering or brazing, and in the same fashion walls 50, 52 can beconnected to walls 44, 46 respectively. In the same fashion, walls 22,24, 26 can be oval or circularly shaped disks with recessed edges toaccommodate walls 28, 30, 32, respectively.

FIG. 2 shows a close up cross-sectional view of upper edge 45 of innercylindrical casing, according to another embodiment of the presentinvention. A peripheral edge of inner wall 52 is bent inwardly aroundthe entire circumference of wall 43 to form an angled edge 55 having anangle α1 relative to a horizontal expansion of the side walls 48, 50,52. Joint or seal 51 is arranged at a tip of angles edge 55 and outersurface of middle wall 50 to form a vacuum seal for vacuum space V3circumferentially around the entire upper edge 45. Analogously, aperipheral edge of middle wall 50 is bent inwardly around the entirecircumference of wall 43 to form an angled edge 53 having an angle α2relative to a vertical expansion of the side walls 48, 50, 52. Joint orseal 49 is arranged at a tip of angled edge 53 and outer surface ofouter wall 48 to form a vacuum seal for vacuum space V4circumferentially around the entire upper edge 45. Moreover, angled edge55 of inner wall 52 and angled edge 53 of middle wall 50 are bent suchthat gaps G2, G3, respectively, is remaining between inner wall 52 andmiddle wall 50, and between middle wall 50 and outer wall 48,respectively, the gaps G2, G3, having exemplary widths of about 0.001 mmto about 5 mm, or from about 0.01 mm to about 1 mm, or from about 0.1 mmto about 0.5 mm, is circumferentially arranged around the respectivewalls. It is noted that upper edge 25 of outer cylindrical casing canhave an analogous structure, with walls 32, 30, 28, instead of walls 52,50, 48, respectively. It should be further understood that a wall mayinclude an extended portion (e.g., a ridge) portion that extends fromthe wall. Such an extended portion may serve to maintain spacing betweenthat wall and an adjacent wall. The extended portion may be used inplace of—or be used with—a spacer ring; spacer rings are described inadditional detail elsewhere herein.

As explained in U.S. Pat. Nos. 7,681,299 and 7,374,063, the geometry ofthe insulating space may be such that it guides gas molecules within thespace toward a vent or other exit from the space. The width of thevacuum insulating space need not be not uniform throughout the length ofthe space. The space may include an angled portion such that one surfacethat defines the space converges toward another surface that defines thespace. As a result, the distance separating the surfaces may varyadjacent the vent such the distance is at a minimum adjacent thelocation at which the vent communicates with the vacuum space. Theinteraction between gas molecules and the variable-distance portionduring conditions of low molecule concentration serves to direct the gasmolecules toward the vent.

The molecule-guiding geometry of the space provides for a deeper vacuumto be sealed within the space than that which is imposed on the exteriorof the structure to evacuate the space. This somewhat counterintuitiveresult of deeper vacuum within the space is achieved because thegeometry of the present invention significantly increases theprobability that a gas molecule will leave the space rather than enter.In effect, the geometry of the insulating space functions like a checkvalve to facilitate free passage of gas molecules in one direction (viathe exit pathway defined by vent) while blocking passage in the oppositedirection.

Another benefit associated with the deeper vacuums provided by thegeometry of insulating space is that it is achievable without the needfor a getter material within the evacuated space. The ability to developsuch deep vacuums without a getter material provides for deeper vacuumsin devices of miniature scale and devices having insulating spaces ofnarrow width where space constraints would limit the use of a gettermaterial.

Although not required, a getter material may be used in an evacuatedspace having gas molecule guiding structure according to the invention.Other vacuum-enhancing features could also be included, such aslow-emissivity coatings on the surfaces that define the vacuum space.The reflective surfaces of such coatings, generally known in the art,tend to reflect heat-transferring rays of radiant energy. Limitingpassage of the radiant energy through the coated surface enhances theinsulating effect of the vacuum space.

In some embodiments, an article may comprise first and second wallsspaced at a distance to define an insulating space therebetween and avent communicating with the insulating space to provide an exit pathwayfor gas molecules from the insulating space. The vent is sealable formaintaining a vacuum within the insulating space following evacuation ofgas molecules through the vent. The distance between the first andsecond walls is variable in a portion of the insulating space adjacentthe vent such that gas molecules within the insulating space aredirected towards the vent during evacuation of the insulating space. Thedirection of the gas molecules towards the vent imparts to the gasmolecules a greater probability of egress than ingress with respect tothe insulating space, thereby providing a deeper vacuum withoutrequiring a getter material in the insulating space.

The construction of structures having gas molecule guiding geometryaccording to the present invention is not limited to any particularcategory of materials. Suitable materials for forming structuresincorporating insulating spaces according to the present inventioninclude, for example, metals, ceramics, metalloids, or combinationsthereof.

The convergence of the space provides guidance of molecules in thefollowing manner. When the gas molecule concentration becomessufficiently low during evacuation of the space such that structuregeometry becomes a first order effect, the converging walls of thevariable distance portion of the space channel gas molecules in thespace toward the vent. The geometry of the converging wall portion ofthe vacuum space functions like a check valve or diode because theprobability that a gas molecule will leave the space, rather than enter,is greatly increased.

The effect that the molecule-guiding geometry of structure has on therelative probabilities of molecule egress versus entry may be understoodby analogizing the converging-wall portion of the vacuum space to afunnel that is confronting a flow of particles. Depending on theorientation of the funnel with respect to the particle flow, the numberof particles passing through the funnel would vary greatly. It is clearthat a greater number of particles will pass through the funnel when thefunnel is oriented such that the particle flow first contacts theconverging surfaces of the funnel inlet rather than the funnel outlet.

Various examples of devices incorporating a converging wall exitgeometry for an insulating space to guide gas particles from the spacelike a funnel are provided herein. It should be understood that the gasguiding geometry of the invention is not limited to a converging-wallfunneling construction and may, instead, utilize other forms of gasmolecule guiding geometries.

FIG. 3 shows a close up cross-sectional view of upper edge 45 of innercylindrical casing 40, according to another embodiment of the presentinvention. In this embodiment, upper edge 45 is formed to have an outersurface that is perpendicular to a horizontal expansion of the sidewalls 48, 50, 52. Instead of having bent portions of side walls 48, 50,52, spacer rings 73 and 71 are arranged to fit at peripheral endsbetween middle wall 50 and inner wall 52, and outer wall 48 and middlewall 50, respectively. Spacer ring 73 is brazed or soldered tocorresponding inner wall 52 with the surface of ring 73 that does nothave a beveled edge to form connection 77, and spacer ring 71 is brazedor soldered to corresponding middle wall 50 with the surface of ring 71that does not have a beveled edge to form connection 75.

A gap G2 remains between side surface of spacer ring 73 having bevelededge with angle α1, and a gap G3 remains between side surface of spacerring 71 having beveled edge with angle α2. Next, gaps G2, G3 are filledwith a brazing material 85, 87 to hermetically provide seals 51, 49 forvacuum spaces V3 and V4. Also, in the variant shown, spacer ring 73 hasa width in a z-direction of D1 that is smaller than a width D2 of spacerring 71. The inner area 60 that is provided inside inner cylindricalcasing 20 and outer cylindrical casing 40 is thereby sealed by twovacuum spaces, being V1 and V2 at the side walls 23 and bottom portion21, and by two vacuum spaces V3 and V4 in an area of lid portion 41. Inaddition, in an area of side walls 23 of the positive z-direction closeto lid portion 41, four vacuum chambers overlie each other. It is notnecessary that a spacer ring have a beveled edge, although such edgesare useful.

The above described embodiment of a vacuum insulated structure 10presents several advantages over conventional vacuum insulatedstructures. First, the presence of at least two vacuum spaces V1, V2and/or V3, V4 along any line from inner area 60 to the outside ofstructure 10 allow to thermally arrange vacuum spaces in series toprovide for improved insulation. Conventionally, to increase insulation,the volume occupied by a vacuum chamber is increased, by simplyincreasing distance between the two walls that form a chamber. However,in certain applications, not enough space is available to simplyincrease the volume of chamber. Without being bound to any particulartheory, the present disclosure provides a solution that allows tosubstantially increase the insulation capacity without having toincrease the overall spacer occupied by a vacuum chamber structure.

Moreover, the presence of two or more vacuum spaces V1-V4 in series alsoallows adds an additional chamber for redundancy purposes. If a vacuumchamber leaks, for example due to aging of seals or a mechanical impact,a second, redundant vacuum chamber is still present to provideinsulation. Also, the arrangement of a shared middle layer 50, 30 fortwo chambers allows to make side walls 23, upper lid 41 and bottomportion 21 that have a mechanical element fully inside the vacuumstructure that serves as an additional insulation barrier for thermalenergy and acoustic noise, because the inner walls 26, 46 and 32 are incontact with inner area 60, and outer walls 22, 28, 48, and 42 are incontact with an environment surrounding the vacuum insulated structure10. Therefore middle walls 30, 50, and middle walls 24, 44 are shieldedfrom direct exposure in both directions, to the inner area 60 and theoutside area. Moreover, the sharing of common middle wall 30, 50 forboth spaces V1 and V2 as well as V3 and V4 allow to reduce weight andcomponents used, as compared to a solution where there are two separatewalls. Conventionally, to improve vacuum insulation, two entirelyseparate vacuumized spaces are used that do not share a common middlewall 30, 50, and are therefore heavier and more expensive.

FIG. 4 shows a close up cross-sectional view of upper edge 45 of innercylindrical casing 20, according to still another embodiment of thepresent invention. In this embodiment, spacer rings 73 and 71 areattached to both middle wall 50 on each side, so that the seal 49 isarranged between spacer ring 71 and outer wall 48, and seal 51 isarranged between spacer ring 73 and inner wall 52. This allows to firstattach spacer rings 71, 72 to middle wall 50 in the same process step,before forming seals 49, 51. Seals 49 and 51 may be spaced out from eachother so that a distance between locations seal 49 and seal 51 ismaximized, so that seals 49 and 51 can be individually formed furtherprocessing of the casing 20, while middle wall 50 can serve as a heatbarrier to prevent a thermal process for forming one seal having animpact on an already formed seal.

FIGS. 5A-5D represent stages of an exemplary method to manufacture edge45 of outer cylindrical casing 40, and to provide for vacuum spaces V3and V4, showing cross-sectional views of the edge 45. Spacer ring 71 isattached to middle wall 50 by soldering. Next, vacuum for vacuum spaceV4 between walls 48 and 50 is formed. Vacuum space V4 may be evacuatedto form a vacuum through a vent 81 located adjacent to edge 45 of wall48. Vent 81 is a small gap between the end of wall 48 and spacer ring71, and is formed circumferentially around edge 45. Vacuum space V4 maybe evacuated by placing the entire structure including walls 48, 50 andspacer ring 71 into a vacuum chamber and then drawing a vacuum in thechamber. As the pressure in the vacuum chamber decreases, gas (usuallyair) escapes from vacuum space V4 via the vent 81. Other methods forapplying suction to the vent 81 may alternatively be used. Theevacuation of for vacuum space V4 achieves a pressure lower than thepressure applied to the vent 81 (i.e., the level of vacuum achieved infor vacuum space V4 is deeper than the level of vacuum applied to thevent 81) as a result of the geometry of spacer ring 71 bounding forvacuum space V4 in the vicinity of the vent 81.

A sidewall of spacer ring 71 may be disposed in the vicinity of the vent81 so as to preferentially direct gas molecules toward the vent 81 in anultra-low pressure free molecular flow regime in which the frequency ofgas molecule collisions with the wall 48 and spacer ring 71 exceeds thefrequency of gas molecule collisions with each other. Without beingbound to any particular theory, the relative geometry of wall 48 andspacer ring 71 adjacent to vent 81 has a guiding effect on gas moleculesin a free molecular flow regime so that the flux of gas molecules outthe vent 81 is greater than the flux of gas molecules into the vent 81.A highly insulating vacuum space V4 having a low vacuum created by suchgeometry can be used in devices of miniature scale or in devices havinginsulating spaces of extremely narrow width. For example, a spacingbetween outer wall 48 and middle wall 50 can be in the order of 0.001 mmto about 5 mm, or from about 0.01 mm to about 1 mm, or even from about0.1 mm to about 0.5 mm.

While vacuum is being applied to the vent 81, outer wall 48, middle wall50, and spacer ring 71 can be heated to accelerate the motion of the gasmolecules within vacuum space V4, so as to further bias the flux of gasmolecules outward from the vent 81 as compared with inward into the vent81 toward vacuum space V4. The temperature used for the heating issuitably lower than the temperature used to bond spacer ring 71 tomiddle wall 50, so that the structural integrity of bond between spacerring 71 and middle wall 50 is maintained. For example, outer wall 48,middle wall 50, and spacer ring 71 may be heated in a combined heatingand vacuum chamber to an elevated temperature and held at thattemperature for a period of time during the evacuation process. Longerhold times may be used to further increase the vacuum achieved in vacuumspace V4. After a desired level of vacuum has been achieved in vacuumspace V4, vent 81 may be sealed to maintain the vacuum. In theembodiment shown, vent 81 is sealable by a first braze material 85 thatmelts and flows into the vent 81 when heated to a brazing temperature,so that end of outer wall 48 is brazed to spacer ring 71 and vacuumspace V4 is sealed off by seal 51. To seal vent 81, a bead of firstbraze material 85 is positioned an inner surface of outer wall 48 facingmiddle wall 50, slightly within vacuum space V4, near vent 81, as shownin FIG. 5A. Before heating and starting the vacuum process, the bead offirst braze material 85 may be solid and is preferably adhered to innersurface of outer wall 48 to form seal 51.

The first braze material 85 is positioned near vent 81 such that duringthe air evacuation process but before the brazing process, vent 81 isnot blocked by the braze material 85. Toward the end of the evacuationprocess, as the desired level of vacuum is being achieved in vacuumspace V4, sufficient heat is applied to outer wall 48 and spacer ring 71to melt the first braze material 85 such that it flows by capillaryaction into vent 81. The flowing braze material 85 seals vent 81 andblocks the evacuation path from vacuum space V4, as shown in FIG. 5B.Flowing of the first braze material 85 is facilitated by any preheatingthat occurs by heating of outer wall 48, middle wall 50 and spacer ring71 during the evacuation phase in order to enhance the ultimate level ofvacuum achieved in vacuum space V4. After maintaining a sufficienttemperature for a sufficient amount of time, first braze material 85forms an alloyed joint or seal 51 between spacer ring 71 and outer wall48. The joint formed by the first braze material 85 is then allowed tocool, so as to solidify and seal vent 81. Alternatively, other processescan be used for sealing vent 81, including but not limited tometallurgical processes or a chemical processes, such as placement of asealing material and then solidification (e.g., via chemical orradiation exposure) of that material. As one non-limiting example, a usemay place a polymeric sealing material at the vent and then solidifythat material by exposing the material to UV radiation. Air- orgas-curable materials are also considered suitable sealing materials.After the joint by brazing material 85 is formed, due to the U-shapedcross section of outer wall 48 and middle wall 50, vacuum space V4 issealed off.

As shown in FIG. 5C, the sealing process may be repeated for vacuumspace V3, in which process vent 83 is sealed by second braze material87. During this process, the temperature of middle wall 50, inner wall52, and spacer ring 73 is kept higher than a temperature of outer wall48 and spacer ring 71, so that the joint formed by first braze material85 does not melt or lose its structural integrity when forming the jointwith second braze material. Next, as shown in FIG. 5D, vacuum seals 49and 51 are formed so that the vacuum spaces V3 and V4 remainvacuum-sealed. In the variant shown, peripheral edges of outer wall 48,middle wall 50, and inner wall 52, as well as surfaces exposed towardsthe negative z-direction are arranged flush to each other to form edge45. It should be understood, however, that the edges or ends of adjacentcomponents need not necessarily be arranged flush with one another,although a flush arrangement may be especially suitable.

In an alternative embodiment, sealing the vents 81, 83 shown in FIG. 5Aand FIG. 5C is performed simultaneously. In this embodiment, first andsecond braze materials 85, 87 are placed on outer wall 48 and middlewall 50, respectively, in proximity to vents 81, 83 to form a circularbead close to the peripheral edges of outer wall 48, and inner wall 50,after spacer ring 71 is attached to middle wall 50. Spacer rings 71 and73 are first attached to the respective walls 50, 52 by soldering usinga temperature that is higher than the temperature required to melt thefirst and second brazing material 85, 87, before the braze materials 85,87 are heated. Thereby, the integrity of the connection of spacer rings73, 71 to middle wall 50 and inner wall 52 is preserved. Then, outerwall 48, middle wall 50, and inner wall 52, as well as spacer rings 73,71 can be heated together in an annealing step to reduce mechanicalstresses formed during the sealing. The method of FIGS. 5A-5D of formingthe sealed edge 45 is described with respect to vacuum spaces V3 and V4,but vacuum spaces V1 and V2 can be made in an analogous fashion, usingwalls 32, 30, 28, instead of walls 52, 50, 48, respectively. It shouldbe understood that any (or all) of the foregoing may be used inconnection with any article or method of the present disclosure.

The present disclosure provides further methods of manufacturing vacuumsealed articles. In some instances, creation of a vacuum (such asdescribed elsewhere herein) between two surfaces can result in thefinished article having a curvature or bend at a vacuum-insulatedregion. As shown in FIG. 6, a user operating on article 600 forms avacuum in the gap 606 between walls 602 and 604. In a beginning state,walls 602 and 604 include a planar region. Following formation of thevacuum and sealing the gap 602 between the walls, however, the finalarticle 600 may exhibit a curved portion, as creation of the vacuumeffects bending of walls 602 and 604. It should be understood thatcurvature is not an inevitable result of forming a vacuum between twosurfaces, as curvature may be the result of particular materialcharacteristics (thickness, material type) and processing conditions andmay not necessarily occur in all instances.

In instances where a user may desire to form a finished article thatincludes a flat region, a user may form a vacuum as described elsewhereherein, but may do so by beginning with a workpiece that has one or morecurved walls. (It should be understood that the term “curved” refers toa curved portion; i.e., a “curved” surface may include flat and curvedregions.)

As shown in FIG. 7, a user may begin with an article 700 that includeswalls 702 and 704; as shown in the figure, walls 702 and 704 bothinclude a curved portion. The user may form a vacuum between the wallsin gap 706 as described elsewhere herein, and as shown in the figure,formation of the vacuum effects bending of the walls such that a curvedportion of the article is at least partially straightened as shown inthe right-hand panel of the figure. In this way, a user can modulate thecurvature of finished articles.

In some embodiments, a tangent to a point on the curved wall may be atan angle A (as shown in FIG. 7) of from about 0.01° to about 90°, fromabout 1° to about 75°, from about 5° to about 45°, or even from about10° to about 30° from the major axis of the wall. For illustrationpurposes, this is shown in FIG. 7 as an angle from the horizontal. Thewall may be processed—e.g., via formation of a vacuum between the walland a neighboring wall—so that the aforementioned angle is altered by atleast about 0.01°, 1°, 10°, 30°, 45°, or even by 60° or even by about90°. It should be understood that in a given article, it is notnecessary for both walls to include curved portions, though somearticles do include such portions. In some embodiments, a first wall maybe straight and a second wall may include a curved portion. A user mayapply heating or cooling to an article during processing so as to modulechanges in the curvature of a wall.

Although a number of exemplary embodiments provided herein presentarticles that include concentric tubes, it should be understood thatarticles according to the present disclosure may feature planar walls,non-tubular walls, or even—in some embodiments—tubes that are notconcentric. FIG. 8 provides one such example—as shown in that figure, anarticle 800 according to the present disclosure may include a vacuumformed in the gap 802 between surfaces 804 and 806. The article may alsooptionally include a third wall 808 such that there is an additionalvacuum formed in the gap 810 between second wall 806 and third wall 808.The ratio of the width of gap 802 to gap 810 can be in the range of fromabout 100:1 to about 1:100, or from about 10:1 to about 1:10. It shouldbe understood that articles according to the present disclosure mayinclude a planar region as well as two vacuum insulated spaces; it isnot a requirement that the vacuum spaces be formed betweenconcentrically-positioned tubes.

It should be understood that a wall may include one or more curvedregions. As shown in FIG. 9, article 900 includes a vacuum formed in thegap 902 between walls 904 and 906; as shown in the figure, wall 904includes undulations. The gap 902 between the walls need not beconstant. An undulation may increase the minimum gap by 5, 10, 15, 20,25, 35, 50, or even 80%. Without being bound to any particular theory,vacuums may be formed according to the disclosures of U.S. Pat. Nos.7,681,299 and/or 7,374,063, both of which are incorporated herein byreference for any and all purposes.

A wall may be formed with a ridged, waved, slotted, or other profilethat confers additional structural rigidity on the wall. As one example,a wall may have a wavy cross-section, as shown by wall 904 in FIG. 9. Awall may also have a corrugated, ridged, or other non-planar structurethat confers additional rigidity onto the wall. An alternativeembodiment is shown in FIG. 12. As shown in that figure, article 1200includes first wall 1204, which wall has a ridged or corrugated profile,which profile confers rigidity on the wall. The first wall 1204 andsecond wall 1206 define vacuum chamber 1202. In this way, a user mayform a vacuum-insulated structure that can maintain its planarconfiguration under atmospheric pressure. A wall may have a non-planarregion and also include a region (which can be the non-planar region)having a corrugated, ridged, or other non-planar structure. As oneexample, FIG. 12 depicts an article 1200 having corrugated wall 1204. Avacuum space 1202 is present between corrugated wall 1204 and planarwall 1206. The wall may also be attached or otherwise connected with aframe that may be used to maintain the wall in a particular position. Asone example, a wall of an article according to the present disclosuremay be attached to frame so as to maintain the wall's surface profile(curvature, planarity, or both) under various ambient conditions.

Vacuum insulated articles according to the present disclosure may also,in some embodiments, include an outer wall, an inner wall, and a middlewall. At least one of the outer wall, inner wall, or middle wall mayhave a planar region. The articles may include an area between the innerwall and the middle wall that defines a first sealed insulating space,and an area between the middle wall and the outer wall defining a secondsealed insulating space; and at least one of the first sealed insulatingspace and second sealed insulating space being at less than ambientpressure. One such exemplary article is shown in FIG. 8. It is not arequirement that both sealed insulating spaces be at below ambientpressure (e.g., at a vacuum), but embodiments where both such spaces docontain a vacuum are considered especially suitable.

Also as described elsewhere herein, at least one of the walls may have aplanar region; in some embodiments, at least two of the outer wall, theinner wall, and the middle wall have planar regions.

An article according to the present disclosure may include a spacerdisposed between the inner wall and the middle wall. The spacer may, insome embodiments, include an edge (which may be beveled) that faces atleast one of the inner wall and the middle wall. Beveled spacers aredescribed and depicted elsewhere herein.

Articles according to the present disclosure may, in some embodiments,include a second spacer disposed between the middle wall and the outerwall. The second spacer may include an edge (e.g, a beveled edge) thatfaces at least one of the inner wall and the middle wall.

The present disclosure also provides methods of fabricating articles.These methods suitably include arranging first and second surfaces(e.g., walls) at a distance from one another so as to define an overlapvolume between the surfaces that has at least one opening placing theoverlap region into fluid communication with the environment exterior tothe overlap volume. The user may maintain a spacing between the surfacesvia placing a spacer or spacers between the surfaces. Alternatively, oneor more surfaces may include a curvature, protrusion, or other geometricfeature that maintains the spacing. At least one of the first and secondsurfaces suitably has a first region that has a curvature.

A user suitably effects a vacuum on the overlap volume by causing air toescape the overlap volume. Methods of applying vacuum are known to thoseof ordinary skill in the art and are described elsewhere herein. Theoverlap volume is then suitably sealed (e.g., via metal brazing) so asto preserve the vacuum within the overlap volume. The methods aresuitably performed under such conditions that the curvature of the firstregion is changed. In this way, the methods may be used to produce anarticle having a planar region after starting with curved surfaces.

As one example, a user may overlap a first planar wall and a secondplanar wall. The user may place a spacer, such as a C-shaped spacerbetween the walls and may even fuse the spacer to the walls such thatthe C-shaped spacer defines a circular volume between the first andsecond walls. The user may then draw a vacuum on the C-shaped volume andthen seal the opening in the C-shaped volume so as to define a sealed,vacuum-containing volume between the first and second walls. Theresultant article may feature planar walls; such an article may becharacterized as being an insulating plate. As described elsewhereherein, the walls of an article may begin as curved and be processed soas to alter—or even eliminate—the curvature of the walls. As describedelsewhere herein, an article may have vacuum insulated spaces betweenfirst and second walls and between second and third walls.

Other methods of forming a vacuum insulated article are provided. Thesemethods suitably include forming a vacuum in a first space definedbetween an outer wall and a middle wall, at least one of the outer andmiddle walls having a planar region that overlaps the first space;forming a vacuum in a second space defined between the middle wall andan inner wall, at least one of the middle and inner walls having aplanar region that overlaps the second space; sealing the first space soas to maintain the vacuum in the first space; and sealing the secondspace so as to maintain the vacuum in the second space. Suitable methodsof forming vacuums are described elsewhere herein.

Still other methods of method of forming vacuum insulated articles areprovided. These methods include, using (a) a first tube having a firstdiameter defined by an outer wall, (b) a second tube having a seconddiameter defined by a middle wall, the second diameter being smallerthan the first diameter, and (c) a third tube having a third diameterdefined by an inner wall, the third diameter being smaller than thesecond diameter.

A user suitably positions the third tube into the second tube to form afirst annular insulating space between the third tube and the secondtube. In some embodiments, the ends of the second tube and the thirdtube are positioned adjacent to each other to form a first circular ventbetween the end of the second tube and the end of the third tube. It isnot a requirement, however, that the ends of the second and third tubesbe positioned so that they are co-terminal with one another, as the endof the second and the end of the third tube may—in some embodiments—beseparated from one another by a distance. As one example, the secondtube may end at a distance of about 1 cm from the end of the third tube.The tubes' ends may be separated from one another by from about 0.001 mmto about 1 mm, 10 mm, or even 50 mm, in some embodiments. In otherembodiments, the tubes may be co-terminal with one another.

A user may suitably draw a vacuum on the first annular insulating spaceby causing air to escape through the first circular vent and may alsosuitably seal the first circular vent to preserve the vacuum within thefirst annular insulating space. Methods for applying vacuum and sealingthe space are known to those of ordinary skill in the art and aredescribed elsewhere herein.

The methods may further include positioning the second tube into thefirst tube to form a second annular insulating space between the secondtube and the first tube. As described above, the ends of the first tubeand second tubes may be positioned adjacent to each other to form asecond circular vent between the end of the first tube and the end ofthe second tube; also as described elsewhere herein, the tubes' ends mayor may not be co-terminal with one another, and the ends may beseparated from one another by a distance, e.g., from about 0.001 mm toabout 50 mm and all intermediate values. The methods also includedrawing a vacuum on the second annular insulating space by causing airto escape through the second circular vent; and sealing the secondcircular vent to preserve the vacuum within the second annularinsulating space; techniques for the foregoing will be known to those ofordinary skill in the art.

The present disclosure further provides vacuum insulated articles. Thesearticles suitably include an outer wall, an inner wall, and a middlewall. The walls may, in some embodiments, be arranged concentricallyrelative to one another. In particularly suitable embodiments, each ofthe outer wall, the inner wall, and the middle wall have a cylindricalshape, although non-cylindrical shapes (e.g., oblong or ovoid) are alsoconsidered suitable.

The articles suitably include an area between the inner wall and themiddle wall that forms a first insulating space, The articles alsosuitably include an area between the middle wall and the outer wallforming a second insulating space.

The article may include in some embodiments a vent communicating withthe first insulating space. This vent may be annular in shape, but thisis not a requirement, as the vent may be slot-, round, oblong, orother-shaped. The article may also include a second vent thatcommunicates with the second insulating space; the second vent. Thesecond vent may be annular in shape, but this is not a requirement, asthe vent may be slot-, round, oblong, or other-shaped. Articles suitablyinclude a seal that seals the first insulating space, which seal may bedisposed at the first vent. An article may also suitably include asecond seal sealing the second insulating space, which seal may bedisposed at the second vent. Metal (e.g., brazed metal) is considered anespecially suitably sealing material.

Articles according to the present disclosure may include a fluid sourcein fluid communication with a volume at least partially enclosed withinthe article. As one non-limiting example, an article according to thepresent disclosure may be in the form of a cylindrical shell comprisedof three (outer, middle, and inner) walls with insulated spaces betweenthe walls. The interior wall may define a space (i.e., a volume)enclosed within the article. This space is thus insulated by thearticle's walls from the environment exterior to the article. A fluidsource (e.g., liquid nitrogen, heated fluid, cooled fluid, etc.) may becoupled or placed into communication with the interior volume of thearticle. As one example, such an article might be coupled to a source ofheated fluid so that a user could manipulate the insulated article anddirect the flow of the heated fluid (e.g., as a sprayer, cannula, orinjector) while also remaining insulated from the heat by the articleitself.

At least one of the first, second, or third walls may have across-sectional dimension in the range of from about 0.01 mm to about 2mm, or even to about 5 mm, about 10 mm, or even about 20 mm. It shouldbe understood that the high insulating ability of the doubly-insulatedarticles allows for reduced wall thickness. At least one of the first,second, and third walls has a cross-sectional dimension in the range offrom about 0.1 mm to about 1 mm, or even from about 0.5 mm to about 0.75mm.

To enhance the insulating properties of the sealed vacuum, an opticalcoating having low-emissivity properties may be applied to the outersurface of an article. The reflective surface of the optical coatinglimits passage of heat-transferring radiation through the coatedsurface. The optical coating may comprise copper, a material having adesirably low emissivity when polished. Copper, however, is subject torapid oxidation, which may increase its emissivity. Highly polishedcopper, for example, can have an emissivity as low as approximately 0.02while heavily oxidized copper may have an emissivity as high asapproximately 0.78. To facilitate application, cleaning, and protectionof the oxidizing coating, the optical coating may be using aradiatively-coupled vacuum furnace prior to the evacuation and sealingprocess. When applied in the elevated-temperature, low-pressureenvironment of such a furnace, any oxide layer that is present will bedissipated, leaving a highly cleaned, low-emissivity surface, which willbe protected against subsequent oxidation within the vacuum space whenthe evacuation path is sealed.

When surfaces (e.g., tubes) are subjected to bending loads, contact mayoccur between adjacent surfaces while the loading is imposed. Thetendency of concentric tubes bent in this fashion to separate from oneanother, or to “springback,” following removal of the bending loads maybe sufficient to ensure that the tubes separate from each other. Contactthat does remain, however, can in some instances provide a detrimental“thermal shorting” between surfaces. To provide for protection againstsuch thermal shorting, a structure may include a spacer material. Such amaterial may be, e.g., yarn or braid comprising micro-fibers of ceramicor other low conductivity material. The spacer layer provides aprotective barrier that limits direct contact between the tubes withoutdetrimentally limiting the flexibility of the structure. Such a spacerlayer may be present between concentrically-arranged tubes, but may alsobe disposed between adjacent planar surfaces.

FIG. 13A depicts an alternative embodiment of the disclosed technology.As shown in that figure, a multi-chamber article may include chambersthat have exits that are characterized as having a converging angle. Asexplained in U.S. Pat. Nos. 7,681,299 and 7,374,063, this convergingexit acts to encourage molecules within the chambers to exit thechamber, improving the vacuum within the chamber. As shown in thatfigure, an article has a first wall 1302 and second wall 1304 thatdefines first vacuum chamber 1306. As shown at the right side of thatfigure, the chamber 1306 has a converging region that encourages theexit of molecules from within that chamber during chamber fabrication.Third wall 1308 defines second vacuum chamber 1310, which second chamber1310 has a converging region as shown in the right-hand side of thefigure. As shown in that figure, the first chamber 1306 and secondchamber 1310 have converging exits at the same ends of the chambers.

FIG. 13B shows a further embodiment of the disclosed technology. Asshown in that figure, first wall 1302 and second wall 1304 define firstvacuum chamber 1306. Second wall 1304 and third wall in turn definesecond vacuum chamber 1310. As shown in FIG. 13B, first vacuum chamber1306 and second vacuum chamber 1310 need not have converging exits atthe same ends of the chambers. As shown in illustrative FIG. 13B, thefirst chamber 1306 has an exit at the right-hand side of the chamber,and the second chamber 1310 has an exit at the left-hand side of thechamber.

FIGS. 10 and 11 depict further embodiments of the disclosed technology.FIG. 10 depicts an end cap structure. The depicted cap includes a lidbrazed in place onto the lid. The lid also includes an insulator throughwhich an electrical conductor or other feed may be passed. The insulatedmay be disposed within a brazed-in-place sleeve disposed in the cap. Thecap also suitably includes a vacuum area; the vacuum area may be definedby a second vacuum chamber as described elsewhere herein. FIG. 11illustrates a container that includes an end cap according to FIG. 10.(The measurements shown in FIG. 11 are exemplary only and do not limitthe figure or this disclosure.)

As shown in FIG. 11, electrical feeds enter the container through endcaps disposed at either end of the container; the container itself mayinclude vacuum-insulated walls. Such containers may be used as, e.g.,battery storage containers or containers for other heat-sensitivearticles.

The foregoing describes the invention in terms of embodiments foreseenby the inventors for which an enabling description was available,notwithstanding that insubstantial modifications of the invention, notpresently foreseen, may nonetheless represent equivalents thereto. Thefollowing aspects are illustrative only and do not serve to limit thescope of the present disclosure or the claims appended hereto.

Aspect 1. A vacuum insulated article, comprising: an outer wall, aninner wall, and a middle wall, each of the outer wall, the inner wall,and the middle wall having a cylindrical shape that are concentric toeach other. The article may include a first insulating space formedbetween the outer wall and the middle wall and a second insulating spaceformed between the middle wall and the inner wall.

The article may also include a first vent communicating with the firstinsulating space to provide an exit pathway for gas molecules from thefirst insulating space, the first vent being sealable for maintaining afirst vacuum within the first insulating space following evacuation ofgas molecules through the first vent. It should be understood that thesealable vent may be closed or sealed. The article may also include asecond vent communicating with the second insulating space to provide anexit pathway for gas molecules from the second insulating space, thesecond vent being sealable for maintaining a second vacuum within thesecond insulating space following evacuation of gas molecules throughthe second vent; a first seal sealing the first insulating space at thefirst vent; and a second seal sealing the second insulating space at thesecond vent.

One or both of insulating spaces may suitably at less than atmosphericpressure. The pressure within an insulating space is suitably less than760 Torr. Pressures of about 10⁻¹, 10⁻², 10⁻³, 10⁻⁴, 10⁻⁵, 10⁻⁶, andeven 10⁻⁷ Torr are all considered suitable.

Aspect 2. The vacuum insulated article of aspect 1, wherein the middlewall is formed of a layer of sheet metal, a first surface of the sheetmetal being in contact with the first insulating space, and the secondsurface of the sheet metal being opposite the first surface of the sheetmetal and being in contact with the second insulating space.

Aspect 3. The vacuum insulated article of any of aspects 1-2, wherein atleast one of the first insulating space and the second insulating spacehas a cross-sectional dimension in the range of from about 0.01 mm toabout 2 mm.

Aspect 4. A vacuum insulated article, comprising: an outer wall, aninner wall, and a middle wall, each of the outer wall, the inner wall,and the middle wall having a cylindrical shape that are concentric toeach other, an area between the inner wall and the middle wall forming afirst insulating space, and an area between the middle wall and theouter wall forming a second insulating space; a first circular ringarranged between the inner wall and the middle wall, the first circularring having a first beveled edge circularly arranged around the firstcircular ring facing at least one of the inner wall and the middle wall,a first vent formed at the first beveled edge communicating with thefirst insulating space; a second circular ring arranged between themiddle wall and the outer wall, the second circular ring having a secondbeveled edge circularly arranged around the second circular ring facingat least one of the inner wall and the middle wall, a second vent formedat the second beveled edge communicating with the second insulatingspace; a first circular insulation seal sealing the first insulatingspace at the first vent; and a second circular insulation seal sealingthe second insulating space at the second vent.

An insulating space may have, as described elsewhere here, a pressuresuitably less than 760 Torr. Pressures of about 10⁻¹, 10⁻², 10⁻³, 10⁻⁴,10⁻⁵, 10⁻⁶, and even about 10⁻⁷ Torr are all considered suitable.

Aspect 5. The vacuum insulated article according to aspect 4, whereinthe middle wall is formed of a layer of sheet metal, a first surface ofthe sheet metal being in contact with the first insulating space, and asecond surface opposite the first surface of the sheet metal being incontact with the second insulating space

Aspect 6. A vacuum insulated article, comprising: an outer wall, aninner wall, and a middle wall, at least one of the outer wall, innerwall, or middle wall having a planar region, an area between the innerwall and the middle wall defining a first sealed insulating space, andan area between the middle wall and the outer wall defining a secondsealed insulating space; and at least one of the first sealed insulatingspace and second sealed insulating spaces being at less than ambientpressure.

As described elsewhere herein, an insulating space may have, asdescribed elsewhere here, a pressure suitably less than 760 Torr.Pressures of about 10⁻¹, 10⁻², 10⁻³, 10⁻⁴, 10⁻⁵, 10⁻⁶, and even about10⁻⁷ Torr are all considered suitable.

Aspect 7. The vacuum insulated article of aspect 6, wherein both thefirst sealed insulating space and second sealed insulating space are atless than ambient pressure.

Aspect 8. The vacuum insulated article of aspect 6, wherein at least twoof the outer wall, the inner wall, and the middle wall have a planarregion.

Aspect 9. The vacuum insulated article of aspect 6, further comprising aspacer disposed between the inner wall and the middle wall, the spacerhaving a first beveled edge facing at least one of the inner wall andthe middle wall.

Aspect 10. The vacuum insulated article of aspect 6, further comprisinga second spacer disposed between the middle wall and the outer wall, thesecond spacer having a beveled edge facing at least one of the innerwall and the middle wall.

Aspect 11. A method, comprising: arranging first and second surfaces ata distance from one another so as to define an overlap volume betweenthe surfaces that has at least one opening placing the overlap regioninto fluid communication with the environment exterior to the overlapvolume, at least one of the first and second surfaces having a firstregion having a curvature; effecting a vacuum on the overlap volume bycausing air to escape the overlap volume; sealing the overlap volume soas to preserve the vacuum within the overlap volume, the method beingperformed such that the curvature of the first region is changed.

Suitable methods of effecting a vacuum are described elsewhere herein,e.g., in U.S. Pat. Nos. 7,681,299 and 7,374,063 and in U.S. patentapplication Ser. No. 12/766,397.

Aspect 12. The method of aspect 11, wherein the sealing comprisesforming a seal by metal brazing.

Aspect 13. A method of forming a vacuum insulated article, comprising:forming a vacuum in a first space defined between an outer wall and amiddle wall, at least one of the outer and middle walls having a planarregion that overlaps the first space; forming a vacuum in a second spacedefined between the middle wall and an inner wall, at least one of themiddle and inner walls having a planar region that overlaps the secondspace; sealing the first space so as to maintain the vacuum in the firstspace; and sealing the second space so as to maintain the vacuum in thesecond space. The vacuum is suitably less than 760 Torr. Pressures ofabout 10⁻¹, 10⁻², 10⁻³, 10⁻⁴, 10⁻⁵, 10⁻⁶, and even about 10⁻⁷ Torr areall considered suitable.

Aspect 14. A method of forming a vacuum insulated article, comprising:with (a) a first tube having a first diameter defined by an outer wall,(b) a second tube having a second diameter defined by a middle wall, thesecond diameter being smaller than the first diameter, and (c) a thirdtube having a third diameter defined by an inner wall, the thirddiameter being smaller than the second diameter, positioning the thirdtube into the second tube to form a first annular insulating spacebetween the third tube and the second tube, such that ends of the secondtube and the third tube are positioned adjacent to each other to form afirst circular vent between the end of the second tube and the end ofthe third tube; drawing a vacuum on the first annular insulating spaceby causing air to escape through the first circular vent; sealing thefirst circular vent to preserve the vacuum within the first annularinsulating space; positioning the second tube into the first tube toform a second annular insulating space between the second tube and thefirst tube, such that ends of the first tube and the second tube arepositioned adjacent to each other to form a second circular vent betweenthe end of the first tube and the end of the second tube; drawing avacuum on the second annular insulating space by causing air to escapethrough the second circular vent; and sealing the second circular ventto preserve the vacuum within the second annular insulating space.Suitable pressures for insulating spaces are described elsewhere herein.

Aspect 15. A vacuum insulated article, comprising: an outer wall, aninner wall, and a middle wall, each of the outer wall, the inner wall,and the middle wall having a cylindrical shape, an area between theinner wall and the middle wall forming a first insulating space, and anarea between the middle wall and the outer wall forming a secondinsulating space; a first vent communicating with the first insulatingspace; a second vent communicating with the second insulating space; afirst seal sealing the first insulating space at the first vent; and asecond seal sealing the second insulating space at the second vent.

Aspect 16. The article of aspect 15, wherein the outer wall, inner wall,and middle wall are arranged concentric to each other.

Aspect 17. The article of any of aspects 15-16, further comprising afluid source in fluid communication with a volume enclosed within thearticle.

Aspect 18. The article of any of aspects 15-17, wherein at least one ofthe first, second, and third walls has a cross-sectional dimension inthe range of from about 0.01 mm to about 2 mm.

Aspect 19. The article of any of aspects 15-18, wherein at least one ofthe first, second, and third walls has a cross-sectional dimension inthe range of from about 0.1 mm to about 1 mm.

Aspect 20. The article of any of aspects 15-19, wherein at least one ofthe first, second, and third walls has a cross-sectional dimension inthe range of from about 0.5 mm to about 0.75 mm.

Aspect 21. A vacuum insulated article, comprising: an outer wall, aninner wall, and a middle wall, an area between the inner wall and themiddle wall forming a first insulating space, and an area between themiddle wall and the outer wall forming a second insulating space; afirst seal sealing the first insulating space at the first vent; and asecond seal sealing the second insulating space at the second vent.

Aspect 22. The article of aspect 21, wherein the outer wall, inner wall,and middle wall are arranged concentric to each other.

Aspect 23. The article of any of aspects 21-22, wherein the firstinsulating space and the second insulating space are at less thanatmospheric pressure, e.g., less than 760 Torr. Pressures of about 10⁻¹,10⁻², 10⁻³, 10⁻⁴, 10⁻⁵, 10⁻⁶, and even about 10⁻⁷ Torr are all alsoconsidered suitable.

Aspect 24: A vacuum insulated article, comprising: an outer wall, aninner wall, and a middle wall, an enclosed volume between the inner walland the middle wall forming a first insulating space and an enclosedvolume between the middle wall and the outer wall forming a secondinsulating space; a first vent communicating with the first insulatingspace; a second vent communicating with the second insulating space; afirst seal sealing the first insulating space at the first vent; and asecond seal sealing the second insulating space at the second vent.

It should be understood that although some embodiments (e.g., aspect 1)comprise cylindrical form factors, the present disclosure contemplatesother form factors. For example, inner, outer, and middle walls may bearranged in a parallel fashion, as shown in non-limiting FIG. 8 The

Aspect 25. The vacuum insulated article of aspect 24, wherein at leastone of the first and second insulating spaces has a pressure of lessthan 760 Torr to about 10⁻⁷ Torr.

Aspect 26. The vacuum insulated article of aspect 24 or aspect 25,wherein at least one of the first insulating space and the secondinsulating space has a cross-sectional dimension in the range of fromabout 0.01 mm to about 2 mm.

It should be understood that in any of the preceding aspects, walls maybe parallel to one another, may converge, or may diverge. Walls need notbe arranged at identical angles; for example, a first wall may be angledat 5 degrees to a reference line, and a second wall may be angled at −10degrees to that same reference line. As described elsewhere herein,walls need not be planar, flat, or even smooth—walls may includeundulations or ridges. The high and low points of an undulation or ridgemay be from 0.001 to 50 mm (and all intermediate values) from oneanother in some embodiments. As one example, the crest of a ridge in awall may be 2 mm away from the trough or low point of that ridge.

It should also be understood that the pressure within an insulatingspace is suitably less than 760 Torr. Pressures of about 10⁻¹, 10⁻²,10⁻³, 10⁻⁴, 10⁻⁵, 10⁻⁶, and even about 10⁻⁷ Torr are all consideredsuitable.

What is claimed:
 1. A vacuum insulated article, comprising: an outerwall, an inner wall, and a middle wall, each of the outer wall, theinner wall, and the middle wall having a cylindrical shape that areconcentric to each other, a first insulating space formed between theouter wall and the middle wall; a second insulating space formed betweenthe middle wall and the inner wall, the first insulating space and thesecond insulating space being in fluid isolation from one another; afirst vent communicating with the first insulating space to provide anexit pathway for gas molecules from the first insulating space, thefirst vent being sealable for maintaining a first vacuum within thefirst insulating space following evacuation of gas molecules through thefirst vent, the first vent being defined by a thickened end portion ofthe inner wall that extends outwardly from the inner wall toward themiddle wall and is sealed to the middle wall; a second ventcommunicating with the second insulating space to provide an exitpathway for gas molecules from the second insulating space, the secondvent being sealable for maintaining a second vacuum within the secondinsulating space following evacuation of gas molecules through thesecond vent, the second vent being defined by a thickened end portion ofthe middle wall that extends outwardly from the middle wall toward theouter wall and is sealed to the outer wall; a first seal materialsealing the first insulating space at the first vent; and a second sealmaterial sealing the second insulating space at the second vent.
 2. Thevacuum insulated article of claim 1, wherein at least one of the firstinsulating space and the second insulating space is at a pressure offrom about 10⁻⁴ Torr to about 10⁻⁷ Torr.
 3. The vacuum insulated articleof claim 1, wherein the inner wall defines a surface that defines anopen container.
 4. A vacuum insulated article, comprising: an outerwall, an inner wall, and a middle wall, the inner wall defining an opencontainer that defines a major axis, an area between the inner wall andthe middle wall defining a first sealed insulating space, and an areabetween the middle wall and the outer wall defining a second sealedinsulating space; a first circular ring arranged between the inner walland the middle wall, the first circular ring having a first beveled edgecircularly arranged around the first circular ring facing at least oneof the inner wall and the middle wall, the first circular ring defininga width measured along the major axis and a first vent formed at thefirst beveled edge communicating with the first sealed insulating spacea second circular ring arranged between the middle wall and the outerwall, the second circular ring having a second beveled edge circularlyarranged around the second circular ring facing at least one of themiddle wall and the outer wall, the second circular ring defining awidth measured along the major axis that is different than the width ofthe first circular ring measured along the major axis, and a second ventformed at the second beveled edge communicating with the second sealedinsulating space; a first circular insulation seal sealing the firstsealed insulating space at the first vent; a second circular insulationseal sealing the second sealed insulating space at the second vent; thefirst sealed insulating space and the second sealed insulating spacebeing in fluid isolation from one another; and the first sealedinsulating space and second sealed insulating space being at less thanambient pressure.
 5. The vacuum insulated article of claim 4, whereinboth the first sealed insulating space and second sealed insulatingspace are at less than ambient pressure.
 6. The vacuum insulated articleof claim 4, wherein at least two of the outer wall, the inner wall, andthe middle wall have a planar region.
 7. The vacuum insulated article ofclaim 4, wherein at least one of the first sealed insulating space andthe second sealed insulating space is at a pressure of from about 10⁻⁴Torr to about 10⁻⁷ Torr.
 8. A vacuum insulated article, comprising: afirst open container comprising an outer wall, an inner wall, and amiddle wall, each of the outer wall, the inner wall, and the middle wallhaving a cylindrical shape, an area between the inner wall and themiddle wall forming a first insulating space, and an area between themiddle wall and the outer wall forming a second insulating space; afirst vent communicating with the first insulating space, the first ventbeing defined by a thickened end portion of the inner wall that extendsoutwardly from the inner wall toward the middle wall and is sealed tothe middle wall; a second vent communicating with the second insulatingspace, the second vent being defined by a thickened end portion of themiddle wall that extends outwardly from the middle wall toward the outerwall and is sealed to the outer wall; a first seal material sealing thefirst insulating space at the first vent; and a second seal materialsealing the second insulating space at the second vent, at least one ofthe first and second insulating spaces being at a pressure of from about10⁻⁴ Torr to about 10⁻⁷ Torr, and, the first container defining aninternal volume having an opening; a second open container, the secondcontainer defining an opening, the opening of the second container beingopposite the opening of the first container.
 9. The vacuum insulatedarticle of claim 8, wherein the first and second containers are sealedto one another so as to interrupt fluid communication between theinternal volume of the first container and the environment exterior tothe internal volume of the first container.
 10. The vacuum insulatedarticle of claim 8, wherein at least one of the inner, middle, and outerwalls has a cross-sectional dimension in the range of from about 0.01 mmto about 2 mm.
 11. The vacuum insulated article of claim 10, wherein atleast one of the inner, middle, and outer walls has a cross-sectionaldimension in the range of from about 0.1 mm to about 1 mm.
 12. Thevacuum insulated article of claim 11, wherein at least one of the inner,middle, and outer walls has a cross-sectional dimension in the range offrom about 0.5 mm to about 0.75 mm.
 13. The vacuum insulated article ofclaim 8, wherein at least one of the first and second insulating spaceshas a pressure of less than 760 Torr to about 10⁻⁷ Torr.
 14. The vacuuminsulated article of claim 8, wherein the second container comprisesinner and outer walls.
 15. The vacuum insulated article of claim 14,wherein the second container comprises an evacuated space disposedbetween the inner and outer walls of the second container.
 16. Thevacuum insulated article of claim 8, wherein the second containerdefines a cylindrical wall, the cylindrical wall facing the outer wallof the first container.
 17. A vacuum insulated article, comprising: afirst open container comprising an outer can, an inner can, and a middlecan, each of the outer can, the inner can, and the middle can having acylindrical shape, the first open container defining a major axis, theinner can comprising an inner bottom joined to a cylindrical inner wallby a rabbet joint; joint, the middle can comprising a middle bottomjoined to a cylindrical middle wall by a rabbet joint; joint, the outercan comprising an outer bottom joined to a cylindrical outer wall by arabbet joint; joint, an area between the cylindrical inner wall and thecylindrical middle wall forming a sealed first insulating space, an areabetween the cylindrical middle wall and the cylindrical outer wallforming a sealed second insulating space; space, a first ventcommunicating with the sealed first insulating space, a second ventcommunicating the sealed second insulating space, a first seal materialsealing the sealed first insulating space at the first vent; vent, and asecond seal material sealing the sealed second insulating space at thesecond vent, at least one of the sealed first and second insulatingspaces being at a pressure of from about 10⁻⁴ Torr to about 10⁻⁷ Torr,and the first container defining an internal volume having an opening;and a second open container, the second container defining an opening,the opening of the second container being opposite the opening of thefirst container, the first container being at least partially disposedwithin the second container, the second container comprising an outerwall, an inner wall, and a middle wall, each of the outer wall, theinner wall, and the middle wall having a cylindrical shape, an areabetween the cylindrical inner wall of the second container and thecylindrical middle wall of the second container forming a first sealedinsulating space of the second container, an area between thecylindrical middle wall of the second container and the cylindricalouter wall of the second container forming a second sealed insulatingspace of the second container; a first vent of the second containercommunicating with the first sealed insulating space of the secondcontainer, and a second vent of the second container communicating withthe second sealed insulating space of the second container, at least oneof the first and second insulating spaces of the second container beingat a pressure of from about 10⁻⁴ Torr to about 10⁻⁷ Torr, and (a) thefirst vent of the second container being defined by a thickened endportion of the inner wall of the second container that extends outwardlyfrom the inner wall of the second container toward the middle wall ofthe second container and is sealed to the middle wall of the secondcontainer; container, a second vent of the second containercommunicating with the second sealed insulating space of the secondcontainer, the second vent of the second container being defined by athickened end portion of the middle wall of the second container thatextends outwardly from the middle wall of the second container towardthe outer wall and is sealed to the outer wall of the second container;container, a first seal material sealing the first insulating space atthe first vent; vent, and a second seal material sealing the secondinsulating space at the second vent, vent; or (b) a first circular ringarranged between the inner wall of the second container and the middlewall of the second container, the first circular ring having a firstbeveled edge circularly arranged around the first circular ring facingat least one of the inner wall of the second container and the middlewall of the second container, the first circular ring defining a widthmeasured along the major axis and a first vent of the second containerformed at the first beveled edge communicating with the first sealedinsulating space of the second container, a first circular insulationseal sealing the first sealed insulating space of the second containerat the first vent of the second container and a second circular ringarranged between the middle wall of the second container and the outerwall of the second container, the second circular ring having a secondbeveled edge circularly arranged around the second circular ring facingat least one of the middle wall of the second container and the outerwall of the second container, the second circular ring defining a widthmeasured along the major axis that is different than the width of thefirst circular ring measured along the major axis, and a second ventformed at the second beveled edge communicating with the secondinsulating space of the second container, a second circular insulationseal sealing the second insulating space at the second vent of thesecond container.
 18. A method of forming a vacuum insulated article,comprising: with (a) a first tube having a first diameter defined by anouter wall, (b) a second tube having a second diameter defined by amiddle wall, the second diameter being smaller than the first diameter,and (c) a third tube having a third diameter defined by an inner wall,the third diameter being smaller than the second diameter, positioningthe third tube into the second tube to form a first annular insulatingspace between the third tube and the second tube, such that ends of thesecond tube and the third tube form a first circular vent between theend of the second tube and the end of the third tube; drawing a vacuumon the first annular insulating space by causing air to escape throughthe first circular vent; sealing the first circular vent to preserve thevacuum within the first annular insulating space; positioning the secondtube into the first tube to form a second annular insulating spacebetween the second tube and the first tube, such that ends of the firsttube and the second tube are positioned adjacent to each other to form asecond circular vent between the end of the first tube and the end ofthe second tube; drawing a vacuum on the second annular insulating spaceby causing air to escape through the second circular vent; and sealingthe second circular vent to preserve the vacuum within the secondannular insulating space, the first and second annular insulating spacesbeing in fluid isolation from one another, and at least one of the firstand second annular insulating spaces is at a pressure of from about 10⁻⁴Torr to about 10⁻⁷ Torr, wherein: (A) the first circular vent is definedby a thickened end portion of the inner wall that extends outwardly fromthe inner wall toward the middle wall, and the second circular vent isdefined by a thickened end portion of the middle wall that extendsoutwardly from the middle wall toward the outer wall; or (B) a firstcircular rim is arranged between the inner wall and the middle wall, thefirst circular rim having a first beveled edge circularly arrangedaround the first circular ring facing at least one of the inner wall andthe middle wall, the first circular vent is formed at the first bevelededge communicating with the first annular insulating space; and a secondcircular ring is arranged between the middle wall and the outer wall,the second circular ring having a second beveled edge circularlyarranged around the second circular rim facing at least one of themiddle wall and the outer wall, and the second circular vent is formedat the second beveled edge communicating with the second annularinsulating space.